1. Field of the Invention
The invention is directed generally toward systems for detecting the presence of fluids, gas or temperatures. More specifically, the invention is directed toward systems for detecting and signaling the presence of fluids on surfaces, gases in the air, or critical temperatures of the air surrounding fluid-containing apparatuses, and manipulating an electronic device that can notify users and prevent further leakage.
2. Description of Related Art
The controlled flow of liquids and gases plays an important role in many facets of residential and business life. Running water in homes, heating water automatically, dispersing coolants in engines, and mixing reactants in chemical production facilities, all require an ability to facilitate and restrict fluid and gas flow on demand. This is typically accomplished by conducting fluids and gases through pipes and/or hoses to a valve. A valve typically has an “on” position that permits fluids to flow past it freely, and an “off” position that completely prevents fluids or gases from flowing past it. A valve may have other positions that allow fluids to flow past it at varying rates. A valve may be connected to a spigot, burner or other means for the liquid or gas to escape its piping. A series of valves may also be positioned between sections of pipe or between conjoined piping systems for more precise transmission and combination of fluids and gases.
Damage, faulty connections, and natural wear in pipe, hose and valve materials can cause them to leak. Leaks may also be caused by freezing of pipes and hoses. Leaks disrupt control over the transfer of fluids and gases, and fluids that escape through the leaks can further damage the pipe and valve materials, as well as surrounding objects. Water leaks and gas leaks can also cause health risks and fire hazards. Only quick detection of leaks can enable a person to prevent such consequences, but leaks in pipes or valves that are concealed from view may not become apparent until some damage is already done. As a result, sensing devices have been invented to aid in detecting a leak and to restrict the flow of liquid toward the leak, thereby minimizing damage.
Past inventions have attempted to provide alarm systems for signaling the presence of water or other liquids at an undesired site. For example, U.S. Pat. No. 4,890,485 to Hsu discloses a housing that encloses an absorbent material. When enough liquid is present, the material expands and pushes a wire through a hollow rod to produce an alarm. U.S. Pat. No. 4,227,190 to Kelley, et al., discloses sensors positioned on the bottom surface of a housing, which is mounted on the bottom of a standpipe. When liquid on a floor reaches a sufficient depth to contact the sensors, an alarm is sounded. While inventions such as these provide detection and notification of leaking fluids, they require a significant amount of leakage to occur before activating an alarm. The amount of fluid that may be released from its piping or other source before reaching the housings in either of these inventions may cause severe damage before the alarm is sounded. Additionally, neither invention provides a means for stopping the leak by shutting off valves that allow fluid to flow towards the leak. This may be problematic where the leak detectors are out of a user's audible range.
Other devices have been invented to detect moisture through the use of electrical potential and conductivity. For example, U.S. Pat. No. 4,325,060 to Purtell, et al., discloses a buoyant housing that has an anode and cathode on its bottom surface. When enough water or other conductive liquid contacts the electrodes to cause the housing to float, a circuit is completed that causes an alarm to sound. U.S. Pat. No. 3,771,349 to Yatabe discloses a device that uses the electrical potentials of dissimilar metals to detect changes in air humidity. Ambient conditions are measured and used as a baseline and compared to areas where leaks might occur, which would typically have higher levels of humidity in the surrounding air. A sample of the air must be drawn into an apparatus in order to test changes in air humidity. While these inventions provide a more sophisticated means of detecting the presence of electrically conductive liquids, they also require a significant amount of liquid to have been leaked into the area before conductivity is achieved by the device. Additionally, while these devices also alert users to the present of undesired liquids, Yatabe lacks the ability to function automatically and neither prevent further leakage.
There are devices which provide shut-off capabilities to prevent fluid flow, upon detection of leaks. U.S. Pat. No. 4,805,662 to Moody uses a solenoid valve that is held open by an electrical current. A second circuit is place within a water collector, such that when water leaking out of a hot water heater collects in the collector, it shorts the second circuit and trips a breaker. This interrupts the current holding the valve open and the valve is closed. U.S. Pat. No. 6,057,770 to Justesen, and U.S. Pat. No. 5,992,218 to Tryba, also work on power interruption principles, but also shut off the gas to the water heater and power to an appliance using water.
U.S. Pat. No. 5,632,302 to Lenoir, Jr., takes the opposite approach. The solenoid valve is disposed in an open position and is only closed if current reaches it. A commercially available water sensor is used to detect leaking water and sends an electrical signal to a power supply. The power supply provides enough electrical current to hold the solenoid valve closed. These devices also include audible and visible indicators that the valve to the water heater has been closed. Though these devices are presumably effective, they are applicable only to detect water leaking from specific appliances. Additionally, the appliances for which these devices are used are typically out of sight, such as water heaters, or their connections to water sources are not easily observable, such as with dishwashers. An alarm or light that indicates a leak may not be heard or seen by persons in normally-trafficked areas of a house or building without excessive noise. More significantly, these devices are not applicable to individual sections of pipe or hose, which are underground or whose sources are controlled by valves at a significant distance from the areas being monitored for leaks.
Subsequent inventions provide remote indication of leaking water. U.S. Pat. No. 5,967,171 to Dwyer, and U.S. Pat. No. 6,025,788 to Diduck, provide radio transmission of signals from water detection means to motorized actuators connected to valves. However, they disclose specific water detection means that are not widely applicable. The Dwyer invention utilizes specific hoses and floor pieces that are designed to maintain a certain level of electrical resistance. When their resistances change due to leaking or contact with water, power is cut to the valves controlling the flow of water and to the appliance using the water. This water detection means is highly specialized and not susceptible of many applications. The Diduck invention uses water-sensing tape that contains tiny apertures through which water may contact a wire. Contact between the wire and water causes a low-voltage electrical short that causes a signal to be sent to a remote actuator that closes the appropriate valve. This type of water sensor may be tripped by small amounts of manually spilled water and even high humidity, making it less reliable than other water sensing means. Additionally, the invention does not notify persons of a leak, particularly those out of visible or audible range.
Hence, there is a great need in the art for a detection system that reliably detects small amounts of liquid or gas, or critical temperatures, which can inform a remote device that such condition has been detected, which can notify a user even if the user is out of visible or audible range, which can reverse a valve position or other device, and which is susceptible of a number of applications and sensitivities without the need for additional iterations of the system's components. Preferably, the system uses switches dependent upon the receipt of threshold voltages, avoiding the dangers of electrical shorts or power interruptions.